From e0fda0f8c492126b30558bbe33e5ddb5e2e6d975 Mon Sep 17 00:00:00 2001
From: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Date: Tue, 10 Mar 2026 20:24:32 +1300
Subject: [PATCH 1/2] Strip trailing OWS from header values. Fixes #47.

---
 lib/protocol/http1/connection.rb          |  9 ++-
 releases.md                               |  4 +
 test/protocol/http1/connection/headers.rb | 98 +++++++++++++++++++++++
 3 files changed, 110 insertions(+), 1 deletion(-)

diff --git a/lib/protocol/http1/connection.rb b/lib/protocol/http1/connection.rb
index 845c2b4..843a7bb 100644
--- a/lib/protocol/http1/connection.rb
+++ b/lib/protocol/http1/connection.rb
@@ -500,7 +500,14 @@ def read_headers
 					break if line.empty?
 					
 					if match = line.match(HEADER)
-						fields << [match[1], match[2] || ""]
+						# The RFCs require stripping of optional whitespace, but only at the end of the field value:
+						if value = match[2]
+							value.rstrip!(" \t")
+						else
+							value = ""
+						end
+						
+						fields << [match[1], value]
 					else
 						raise BadHeader, "Could not parse header: #{line.inspect}"
 					end
diff --git a/releases.md b/releases.md
index 7755873..87cafb0 100644
--- a/releases.md
+++ b/releases.md
@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - Strip optional whitespace (OWS) from the end of header field values when parsing headers.
+
 ## v0.37.0
 
   - `Protocol::HTTP1::BadRequest` now includes `Protocol::HTTP::BadRequest` for better interoperability and handling of bad request errors across different HTTP protocol implementations.
diff --git a/test/protocol/http1/connection/headers.rb b/test/protocol/http1/connection/headers.rb
index c43dbaa..41b872a 100644
--- a/test/protocol/http1/connection/headers.rb
+++ b/test/protocol/http1/connection/headers.rb
@@ -207,5 +207,103 @@ def validate_headers!(expected_headers = self.headers)
 				end.to raise_exception(Protocol::HTTP1::BadHeader)
 			end
 		end
+		
+		with "a header with leading whitespace (spaces)" do
+			let(:headers) {[
+				"x-test:   here it is"
+			]}
+			
+			it "strips leading spaces" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
+		
+		with "a header with leading whitespace (tabs)" do
+			let(:headers) {[
+				"x-test:\t\there it is"
+			]}
+			
+			it "strips leading tabs" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
+		
+		with "a header with leading whitespace (mixed)" do
+			let(:headers) {[
+				"x-test: \t \there it is"
+			]}
+			
+			it "strips leading spaces and tabs" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
+		
+		with "a header with trailing whitespace (spaces)" do
+			let(:headers) {[
+				"x-test: here it is   "
+			]}
+			
+			it "strips trailing spaces" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
+		
+		with "a header with trailing whitespace (tabs)" do
+			let(:headers) {[
+				"x-test: here it is\t\t"
+			]}
+			
+			it "strips trailing tabs" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
+		
+		with "a header with trailing whitespace (mixed)" do
+			let(:headers) {[
+				"x-test: here it is \t \t"
+			]}
+			
+			it "strips trailing spaces and tabs" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
+		
+		with "a header with both leading and trailing whitespace" do
+			let(:headers) {[
+				"x-test: \t here it is \t "
+			]}
+			
+			it "strips both leading and trailing whitespace" do
+				authority, method, target, version, headers, body = server.read_request
+				
+				expect(headers).to have_keys(
+					"x-test" => be == ["here it is"]
+				)
+			end
+		end
 	end
 end

From d6009f4522744778dfe48993a7bc7beb9339f14f Mon Sep 17 00:00:00 2001
From: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Date: Tue, 10 Mar 2026 20:39:25 +1300
Subject: [PATCH 2/2] `rstrip` on Ruby 3 does not accept an argument.

---
 lib/protocol/http1/connection.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/protocol/http1/connection.rb b/lib/protocol/http1/connection.rb
index 843a7bb..4304756 100644
--- a/lib/protocol/http1/connection.rb
+++ b/lib/protocol/http1/connection.rb
@@ -502,7 +502,7 @@ def read_headers
 					if match = line.match(HEADER)
 						# The RFCs require stripping of optional whitespace, but only at the end of the field value:
 						if value = match[2]
-							value.rstrip!(" \t")
+							value.rstrip!
 						else
 							value = ""
 						end